mixed revisions after update

I'm new to svn and learning by practice. I don't use the CLI, but installed Tortoise on winxp.  I'm reading the book bit by bit and now I have a questions of which I hope this is the right please to ask.    I read, or think to understand, that after a update, my whole working directory would be updated to the latest revision number.  This is not the case. Did I misunderstand the concept is is something else going wrong?

Last updated 15 years ago

Read the section on Mixed Revisions in the manual.    (Then read the rest of the manual) :D

Only by running svn update can the latest changes be downloaded, and the whole working copy be marked as revision 15.    What is meant by "the whole working copy". Is it all the files commited in one go? I thought it was "my whole working directory" That's not so then?